Guide bushing for drills



Nov.21, 1944, R. T. ROYE I GUIDE BUSHING FOR DRILLS- Filed Nov. 29,1943' drawing wherein:

Patented Nov. j 1944 STATES NT- OFFICE GUIDE BUSHING Eon DRILLS eRichard T. Roye, Houston, Tex.

Application November 29, 1943, ser al No. 512,231

(Cl. 77-.62l

4 Claims.

This invention relates to a guide bushing for drills. i

An object of the invention is to provide a novel type of guide bushingadapted to be in serted into a suitable fixture and provided for guidinga drill which operates through the bushing.

The type of bushing herein described is specially useful to preventdeflection of the drill in case the drill contacts the surface of otherthan a right angle.

A further object of the invention is to provide the work at a bushing ofthe character described which is i sectional so that only the section ofthe bushing subjected to the greatest wear may be discarded,

when worn, and the remaining portion of the i bushing may be re-used foran indefinite length of time.

With the above and other objects in view the invention has particularrelation to certain novel features of construction, arrangement of partsand use, an example of which is given inthis specification andillustrated in the accompanying Figure 1 shows a cross sectional view ofthe work and fixture showing the drill bushing in section with the drilltherein, taken on the line l--I of, Figure 2. 1 i

Figure 2 shows asectional view taken on the line 2-2 of'Figure 1. iFigure 3 shows a side elevation of the detachablesolid end of thebushing.

Figure 4 shows an end iew of said section, and

Figure 5 shows an enlarged, fragmentary, sectional view taken on theline l-l of Figure 2.

Referring now more particularly to the draw- In drilling the bore or keyway a fixture 3 is fitted over the'work. This fixture has a bore 4 to ireceive a bushing. The bushing is made of very hard material and at thepresent time is formed of one piece with a longitudinal bore entirelytherethrough to receive the drill and with itsinner end tapered to fitagainst thesurface of the work. In practice, however, it has been foundthat when that typeof bushingis used there will be a slightdefiection ofthe work, that is, in the i event said surface is at other than a rightangle to the axis of the drill; and this deflection will vary somewhatasthese key ways are drilled depend 'ing on variations in thehardness ofthe material of the work; and furthermorethis deflection of i the drillpoint causes wear and the enlargement of the inner end of the borethrough the drill bushing so that the bushing must be discarded and anew one used foreach bore, or key way drilled. i

In the present invention the drill bushing is j i made sectional, theouter section being tubular 1 and, indicated by the numeral 5 and theinner section 6 being initially solid.

I cut through the face 1 and start the bore into the U fitting l beforethe pointof the drill has comi ing, whereinlike numeralsof referencedesignat the same parts in each of the figures, the numeral l designatesa tubular fitting adapted to be fitted over a cylindricalpart 2, such,for example, as a gun barrel.

It is contemplated that a key way will be drilled throughsaid parts toreceive a pin, or key, to,

i any deflection of the drill and all ofthe bores fasten the fitting Iimmovable on the barrel 2. i

This key way will be bored partly in the fitting and partly in thebarrel as illustrated by dotted is to be drilled, the inner section 6may be dislines in Figure 1; In producing these parts in quantity it isvery important that thesebores or key ways be accurately drilled so thatthe fittings barrel 2, the key ways will precisely aline.

It is contemplated that when the bore, or key I will be interchangeableand when fitted on any way, has been completed, a pin or key will bedriven into the bore and its ends riveted so as to secure the partstogether. i

As clearly indicated in Figures 1 and 3; the

inner section has its inner end formed with a tapering face 1 tofitagainst the external. surface of the fitting I.

The numeral 8 designates to be driven in any suitable manner.

In operation the parts are assembled as shown,

in Figure land the drill is inserted through the bushing section 5 andasit is rotated it will form a bore through'the solid section 6. Asisillustrated in Figure 5,the, cutters of the drill will pleted the borethrough the solid section of the fitting and this solid section 6 W111hold the drill in a true course, and will prevent its deflection, untilthe bore has been started in the fitting. The bore or keyway may then becompleted without will be precisely alike.

After one bore has been completed and, another carded and anothersolidsection substituted for it and the outer section 5 of the bushing maybere-used. It is standard practice now, when aone piece bushing is used,to discardthe entire bushing, on account of slight 'wear and use a newbushing for each bore or key way drilled.

The drawing and description are, illustrative only, while the broadprinciple of the invention will be defined by theappended claims.

the drill which is What I claim is:

1. A' guide bushing for drills comprising an outer tubular section andan inner solid section.

2. A guide bushing for drills comprising an outer tubular section and aninner solid section 5 whose inner end is diagonal.

3. A guid bushing for drills comprising two abutting sections ofapproximately the same transverse diameter, the outer section beingtubular and the inner section beingsoiid, the abutting end faces of thesections being at substantially right angles to the longitudinal axis ofthe bushing and the inner end face of the solid sec tion being diagonalto said axis.

4. The combination with fixture having an approximately circular workreceiving opening and having a bore through the fixture extending V intothe opening and whose axis is on a chord I of the circle defined by saidopening, of a guide bushing for a drill in said bore; said bushing beingformed of a tubular outer section and a solid inner section, the innerend of said inner section being tapered and being approximately flushwith 10 the wall of said opening.

RICHARD T. ROYE.

